Worksheet on forces and motion featuring a diagram of a person pulling a dog.

Let’s go step by step through each question.

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c) If the forward and backward forces are balanced, what will happen to the speed of the car?

When forces are balanced, there is no net force acting on the object. That means the car won’t speed up or slow down — it will keep moving at the same speed (or stay still if it was already stopped).

→ Answer: The speed of the car will stay the same.

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d) If the forward force is bigger than the backward force, what will happen to the car?

If the forward force is stronger, the car will start to move faster in the forward direction — it will accelerate.

→ Answer: The car will speed up (accelerate) forward.

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e) If the backward force is bigger than the forward force, what will happen to the car?

Now the backward force wins — so the car will slow down if it’s moving forward, or maybe even start moving backward.

→ Answer: The car will slow down (decelerate) or move backward.

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f) Give the name of another force which could be acting on the car.

Besides forward and backward forces, cars also experience gravity pulling them down, and the ground pushing them up (normal force). Also, air resistance or friction might act against motion.

→ Answer: Gravity (or Friction, or Air Resistance)

*(Any one of these is fine — let’s pick “Gravity” as it’s always acting.)*

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g) Which direction will it be acting in?

Gravity pulls everything downward toward the Earth.

→ Answer: Downward

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Now for Question 4 — Linda and the dog:

a) Draw an arrow on the diagram to show the direction of the force Linda is applying.

Linda is pulling the rope to try to get the dog to move. So she’s pulling the rope toward herself — that’s to the right (assuming the dog is on the left and Linda is on the right).

→ Arrow should point from the dog toward Linda (to the right).

*(Since we can’t draw here, we describe it: Arrow pointing right along the rope, starting near the dog’s collar or where Linda holds the rope.)*

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b) The dog is pulling on the rope. Draw an arrow on the diagram to show direction of this force if the dog does not move.

The dog is resisting — pulling back against Linda. So the dog’s force is opposite to Linda’s — to the left.

→ Arrow should point from Linda toward the dog (to the left).

*(Again, described: Arrow pointing left along the rope, showing the dog pulling back.)*

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c) When the rope breaks, what will happen to:

i) the dog?

The dog was pulling backward. Once the rope breaks, there’s nothing holding it back anymore — but since it wasn’t moving before, and now the tension is gone, it might just sit there… unless it suddenly lunges forward because it was straining against the rope. But based on physics, if the dog was stationary and the rope breaks, the dog may jerk forward slightly due to release of tension — but more accurately, since the dog was applying a force backward, when the rope breaks, that force is no longer countered — so the dog might fall or lurch backward? Wait — let’s think again.

Actually, if the dog is sitting and pulling backward on the rope, and the rope breaks, the dog loses the opposing force from Linda. But the dog itself isn’t being pulled forward — it’s pulling backward. So when the rope breaks, the dog might stumble backward a little because it was leaning into the pull.

But in most textbook answers, they say: the dog will move backward (because it was pulling hard and suddenly has no resistance).

Wait — better way: Think of Newton’s Third Law. The dog pulls the rope left, the rope pulls the dog right. When the rope breaks, the rope no longer pulls the dog right — so the dog, which was trying to pull left, might actually move left? No — confusion.

Let’s simplify:

- Dog is sitting, pulling rope to the left.
- Rope pulls dog to the right (equal and opposite).
- Net force on dog = zero → doesn’t move.
- Rope breaks → rope no longer pulls dog to the right.
- Now only force on dog is its own muscle pull? But muscles don’t push/pull without something to react against.

Actually, once the rope breaks, the dog is no longer connected to anything. Since it was sitting still, and no external horizontal force acts on it after break, it should remain still — unless it reacts emotionally!

But in science terms: Before break, two forces on dog:
1. Dog’s paws push ground backward → ground pushes dog forward (friction)
2. Rope pulls dog forward (tension)

Wait — I think I had it backwards.

Standard interpretation:

- Linda pulls rope → tension pulls dog toward Linda (right).
- Dog resists → dog’s feet push ground backward → ground pushes dog forward (left) via friction.
- So forces on dog:
- Tension from rope → right
- Friction from ground → left
- Balanced → dog doesn’t move.

When rope breaks:
- Tension disappears.
- Only friction remains? But friction only exists if there’s tendency to move. Actually, if the dog stops pulling, friction goes away too.

But realistically, when the rope breaks, the dog was exerting effort to pull left. Suddenly, no resistance — so the dog might fall or lurch to the left (backward relative to Linda).

Most expected answer:

→ i) The dog will fall or move backward (away from Linda).

Similarly for Linda:

She was pulling hard to the right. When rope breaks, she loses the resistance — so she might stumble forward.

→ ii) Linda will fall or move forward (in the direction she was pulling).

This matches common sense and basic physics of unbalanced forces upon sudden removal of constraint.

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Final Answers compiled:

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Final Answer:
c) The speed of the car will stay the same.
d) The car will speed up (accelerate) forward.
e) The car will slow down (decelerate) or move backward.
f) Gravity
g) Downward
4a) Arrow pointing to the right (from dog toward Linda)
4b) Arrow pointing to the left (from Linda toward dog)
4ci) The dog will fall or move backward (away from Linda).
4cii) Linda will fall or move forward (in the direction she was pulling).